Lawn-mower.



No.'807,7 3' 7,." PATENTED DEC. 19, 1905. P. H. PRANKENBERG.

LAWN MOWER.

APPLICATION FILED J ULY3, 1905.

Q vil'nmacs UNITED sawrns PAlENT OFFICE.

LAWN-MOWER.

Specification of Letters Patent.

Patented Dec. 19, 1905.

Application filed July 3, 1905. Serial No. 268,061.

My invention relates to attachments for lawn-mowers; and its object is to provide a simple, durable, and inexpensive device which can be readily connected to a lawn-mower and by means of which the blades of the machine can be quickly and thoroughly sharpened either during or prior to the use of the V lawn-mower.

A still further object is to provide means whereby an equal pressure will be maintained by the sharpening device.

A still further object is to employ means for throwing the attachment into or out of operative relation with the blades and for regulating the angle of the cutting edge produced thereby.

With the above and other objects in view the invention consists of a socket adapted to be fastened to the handle of a lawn-mower and having a blade pivoted therein and to which is adjustably connected an arm having means for limiting its movement toward the handle. A holdingblock is hinged to the arm and is provided with means for supporting it at a desired angle in relation thereto, and this holding-block is provided with a sharpening device. such as a slab of stone, steel, or other suitable material, adapted to be successively contacted by the rotary blades of the lawn-mower.

The invention also consists of the further novel contructions and combinations of parts hereinafter more fully described, and pointed out in the claims.

In the accompanying drawings I have shown the preferred form of my invention.

In said drawings, Figure 1 is a longitudinal section through a lawn-mower and also my improved attachment contacted thereto, and Fig. 2 is a perspective view of the attachment with its spring removed.

Referring to the figures by numerals of reference, 1 isalawn-mower having rotary blades 2 and a handle 3, all of which may be of any preferred construction. Secured upon the handle is a socket, consisting of a base 4:, having ears 5 for the reception of the screws 6 and parallel flanges 7 projecting upward from the base and supporting a pivot-pin 8. This pin extends through and constitutes a bearing for a blade 9, which extends into the socket and is adapted to rest between the flanges thereof. The free end of the blade 9 is slotted longitudinally, as shown at 10, and projects into a slot 11, formed within an arm 12. Bolts 13 are fitted within the walls of slot 11 and extend through slot 10, and these bolts are adapted to clamp the walls of slot 11 upon the blade 9, so as to hold the .two parts in any relation to which they may be adjusted. A slot 1 1 is formed in the arm 12 near its front end, and hinged to this end of the arm is a holding-block 15. formed of any suitable material and having a slab 16 of emery, steel, or any other desired material of suflicient hardness to constitute a grindingsurface. A threaded stem 17 is secured to the holding-block 15 and is adapted to swing within slot 14. A thumb-nut 18 ismounted on the stem 17 and constitutes a support for the block 15 for the purpose of holding the same at any desired angle to arm 12. A bow-- spring 19 is secured to the blade 9 and contacts at its free end with one end of the socket 7. A holding-nut 20 is arranged on stem 17 for preventing upward movement of said stem in slot 14:.

It will be understood that the attachment can be readily secured upon the handle 3 of a lawn-mower by means of screws 6, and after being once placed thereon the arm 12 can be adjusted longitudinally so as to bring the end thereof above the rotary blades of the machine. By turning the thumb-nut 18 the block 15 can be adjusted upward or downward so that the longitudinal center of the slab 16 will lie within the path of the blades 2. The machine can then be pushed forward, and as the blades rotate they will successively strike the slab 61, and by sliding thereon their cutting edges will be ground. It will of course be understood that each time the slab is contacted by a blade said slab will be pressed upward and will cause the nut 20 to press the arm 12 away from handle 3. As soon as the blade passes from under the slab the device will drop by gravity into position to contact with another blade 2, and this return movement of the attachment will be assisted by the bow-spring 19. The downward movement of the attachment may be regulated by a setscrew 21, which extends through the arm and normally contacts with the handle 3.

It will be understood that when it is desired to throw the attachment out of operative relation to the blades this can be quickly accomplished by turning the screw 21, so as to force the arm 12 away from handle 3 a sufficient distance to remove slab 16 out of the path of blades 2.

It will be seen that this device is very simple in construction and can be readily adaptcd to any form of mower having rotating blades and does not require the services of an expert to sharpen the blades. The-angle at which the blades are sharpened can be quickly regulated by means of the thumbnut 18 and holding-nut 20.

1t.will be noted that the pin 8 not only constitutes a bearing for the blade 9, but can also be quickly withdrawn, so as to enable the entire attachment to be removed from the socket. The screws 6 herein referred to constitute adjusting devices for holding the socket firmly in place should the same be secured upon an uneven or rounded surface. I attach considerable importance to the fact that the attachment can be very quickly removed by simply withdrawing the pin 8.

. The set-screws 6,in addition to their function of holding the socket rigidly upon an uneven or rounded surface, also permit the attachment to be adjusted so that the grindingsurface can be brought into a plane parallel with the cutting edges of blades 2.

Having thus fully described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. A sharpening attachment for mowers comprising a longitudinally-adjustable pivoted arm, a sharpening member hinged to said arm, means for locking said member to any desired angle to the arm and adjustable supporting means extending from the arm.

2. A sharpening attachment for mowers comprising a base, a longitudinally-adjustable arm pivoted thereto, a sharpening member hinged to the arm, means for securing, 5 sald member at any desired angle to the arm l and adjustable supporting means extending from the arm.

3. A sharpening attachment for mowers comprising a base, a longitudinally-adjustable arm pivoted therein, a sharpening member hinged to the arm, adjustable means for locking said member at any desired angle to the arm, and resilient means secured to the arm and bearing upon the base for holding said arm in a predetermined position.

4. The combination with a mower having rotary blades; of a sharpening attachment secured to a portion of the mower and comprising a pivoted arm, a sharpening member hinged to the arm and adapted to rest in the path of the blades, and adjustable means upon the arm and contacting with the mower for normally supporting the sharpening member in desired relation to the blades.

5. The combination with a mower having rotary blades; of a sharpening attachment secured to the mower and comprising a pivoted arm, means for securing said member at a desired angle to the arm, and an adjusting device extending through the arm and into contact with the mower.

6. The combination with a mower having rotary blades and a handle; of a grinding attachment comprising an arm pivoted to the handle, a grinding member hinged to the arm and adapted to rest by gravity in the path of the blades, and an adjusting device extending through the arm into contact with the handle.

7. The combination with a mower having rotatable blades and a handle; of a longitudinally-adjustable arm pivoted upon the handle, an adjusting device extending therethrough into contact with the handle, asharpening member hinged to the arm and adapted to assume by gravity a position in the path of the blades, and means for locking said member at a desired angle to the arm.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

FRANK H. FRANKENBERG.

Witnesses:

M. J. MoDoNNELL, R. L. HUNTZINGER. 

